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3 "fiddy" for short
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Discussion Starter · #1 ·
I was just wondering if anyone here has a good diagram that contains detailed drawings of the internal workings of the Van RLC and DHX air? If so could you post them?
Thanks in advance fellas!
 

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be350ka said:
I was just wondering if anyone here has a good diagram that contains detailed drawings of the internal workings of the Van RLC and DHX air? If so could you post them?
Thanks in advance fellas!
Fox has a downloadable PDF Manual from it's website, unfortunately the schematics are vary elementary, http://www.foxracingshox.com/fox_tech_center/owners_manuals/06_32mm_en.pdf

I don't know if this helps any, a link on servicing the Vanilla: http://www.enduroforkseals.com/id28.html
 

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3 "fiddy" for short
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Discussion Starter · #3 ·
:cool: Thanks. What I am in search of, for some reason, is a nice color schematic that shows airflow path, oil exchange, etc. More for personal knowledge that anything else. But again, thanks for your contribution. I will take a look at the rebuild link.
 

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carpe mañana
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What exactly are you interested in knowing? I don't have any schematics but I can probably give you a fairly detailed explanation.

_MK
 

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3 "fiddy" for short
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2,739 Posts
Discussion Starter · #5 ·
Basically I am looking for a better understanding of the adjustments of the DHX Air. Others have stated the correlation between the boostvalve and propedal and how they affect the ride, etc. It really is a fine shock but I do find myself getting a little confused at times when I start thinking about making changes and what I should be looking for on the trail when I make more than one adjustment. I know, never think, but its hard. I remember Darren posting some info on this forum earlier but cant find it. So, thanks for your help.

As far as the Vanilla goes, I am just interested to see what the valving looks like to see how the Push treatment affects the internal "flow" .

Kinda dorky I know, but I am interested in knowing more about my suspension. :)

350
 

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carpe mañana
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I'll keep silent about PUSH as I don't know how much Darren wants disclosed. Not that I know all of it, however he has shown me some of it and talked about a lot of the rest. In any case, it's his business (literally, huh?) how he does things.

About the DHXair. So the damper and the boost chamber are conneced by a little orifice which is kept closed by an oil metring valve called, you guessed it, the Boost Valve. Behind the valve is a piston which separates the oil from the boost chamber air. In addition, there's a piston inside of the damper which is shimmed bi-directionally, meaning, there are shims for compression and there are shims for rebound.

So, the damper is filled with oil, completely, there's no air there whatsoever. When you compress the shock, oil is being forced through the shimmed piston and the boost valve into the reservoir, however, the valve which meters the oil flow into the reservoir is being kept closed by the air pressure in the boost chamber. Eventually, the force of oil overcomes the force of air and oil begins to flow into the reservoir. Oil flowing into the reservoir is pushing down the piston which reduces the air volume in the boost chamber. This causes the air pressure to go up, which in turn exerts more force on the metering valve, wanting to close it. At the end of the stroke the force of air begins to overcome the force of oil, closing the metering valve and preventing harsh bottomout. Depending on you BO adjustment, the air chamber has a given size to begin with. If it is a smaller chamber (BO screwed in) the force of air rises faster, if the chamber size is larger, it raises slower. Ideally you would have it set so that it slows down the shaft speed at the end of the stroke enough to prevent a hard bottomout.

Propedal is simply a little coil spring which preloads the metering valve. It is a coil assist to the air pressure in the boost chamber. I have found that effectively, you can achieve the exact same pedaling characteristic by upping the pressure in the boost chamber slightly while gaining a smoother stroke, because the force of coil very quickly is overcome by the force air and oil and you can feel a little harshness at the transition.

Hope this helps. If anything isn't clear, let me know.

_MK
 

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3 "fiddy" for short
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Discussion Starter · #7 ·
That was a big help. That is exactly the type of explanation I was looking for. Seeing it on paper would probably paint a good picture in conjunction with your discription, but I now have what I need. Thanks so much for your help and your willingness to help others learn.

350 :cool:
 

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suspension whore
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thx

thanks for this- I was curious about the same stuff
I would have thought that the pro- pedal spring assist worked on the main chamber at the beginning of the stroke- not the boost chamber?, creating a little platform on the top of the main chamber travel for pedal input that you could blow through easilly on big hits?
i have mine turned all the way down on my VPP 6.6 but i was just curious.
thanks for the oil reserve description. I was trying to figure out how air didnt flow from one chamber to the other or how it activated but your description makes perfect sence
 

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carpe mañana
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matthew said:
I would have thought that the pro- pedal spring assist worked on the main chamber at the beginning of the stroke- not the boost chamber?, creating a little platform on the top of the main chamber travel for pedal input that you could blow through easilly on big hits?
The main chamber and the boost chamber are connected via the metering valve on which the spring assist works. When oil pressure is low, as in the begging of stroke/static sag, the spring force has a large effect on the position of the metering valve. When the shock starts moving, especially quickly, like on big hits, the force of that little spring is marginal compared to the oil and air forces. So it does in fact act throughout the whole range of stoke, however, it is only a significant factor at the early stage of low speed shaft movement, like pedaling.

_MK
 
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